It appears that autogen.sh doesn't like es.po if it isn't mentioned in
[tinc] / cvsusers
1 zarq:Ivo Timmermans <itimmermans@bigfoot.com>
2 guus:Guus Sliepen <guus@sliepen.warande.net>
3 wsl:Wessel Dankers <wsl@nl.linux.org>